In my country school for kids ends at 4pm, but they have extra-curricular activities (gym, music/theater and English) up to 5:30pm. The fact is those activities are taught in a chaotic classroom and those teachers that only give one hour per day don't have any sort of authority. Makes me wonder... what is my kid doing there?
Extra-curricular activities are great for kids because among other things because: a) Kids get to learn [important] social skills. b) They [extra-curricular activities] help with a kids emotional development. c) Kids get learn about time-management. And those are but a few of the benefits . . .
I do agree that both music, English and physical education are something important, but they are not learning time-management, they are just like little sheep that go to where they are told. Music is very important, but it's not just music, it's called "expressions" these days, whatever that is.